[Diy_efi] some pictures...

[Mike]

At 09:11 PM 7/4/06, you wrote:
>I've heard a lot of what I think is probably snake-oil from turbo recon people who tend to claim the whole thing needs special balancing.

It *is* correct, these things spin at rather high rates, 80,000 to 120,000 rpm
and really do need to be balanced after re-assembly or they will howl and
can oscillate and effectively explode at high revs but not necessarily straight
away - it depends how long, what load etc. Proper balancing will ensure it
lasts the full service life, pot luck with no balancing and only assembly
means you could be anywhere in terms of dynamics and that means it
can fail at any time and probability suggests it will not reach a fraction
of its service life if you expect it to provide any power and that means
high revs...

Note: Even if you reassemble carefully you still must get it balanced.
Minor variations in static balance due to nonhomogenous material
densities *anywhere* mean that rotating the assembly by a few degrees
without changing anything else *will* change dynamic balance drastically !

Static balance might just be ok to around 5000rpms *but* any speed
even 10% of max revs really does need dynamic balancing, if I recall
correctly there is a 3rd or 4th order exponent involved - so its absolutely
essential... ie Not snake oil at all.

Rgds

mike






>It seems to me that the balancing has been done by grinding the inner face of the ehaust turbine and the outer 'nub' on the end of the shaft - neither of which is adjustable in any real sense, so my thought is that the shaft/turbines are balanced and pretty much anything else is just careful assembly.
>
>bfn!
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